You may have heard about that oarfish that washed up on Aliso Beach in 1922, giving rise to talk of sea serpents. But have you heard of "Santiago Sam," the bigfoot/sasquatch that shows up occasionally in the Santa Ana Mountains? Rumor has it that he's only about 5' 2", which makes him the shortest bigfoot ever recorded, but he still leaves enormous 20" footprints behind. (The photo below is an example of a similarly sized footprint.) Sam's short stature has probably allowed him to remain mostly hidden in the scrub brush of the Santa Anas. 
There have been four sightings (reported to me by Rangers who preferred not to be idenitified) in or adjacent to Black Star Canyon, with other sightings scattered across both the Riverside and Orange County portions of the Cleveland National Forest. .
In his Boys Book of Bear Stories, historian Jim Sleeper points out that although bears have long been considered exterminated from our mountains, there are still occasional verifiable sightings. If animals as large as bears can remain well hidden in that terrain, it's certainly reasonable that a critter the size of Santiago Sam could keep a pretty low profile.
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If you know of any additional local cryptozoological lore, please let us know in the comments section below.